Detecting exaggeration and malingering with the trail making test

The purpose of this study was to examine whether unusual performance on the Trail Making Test could be indicative of deliberate exaggeration. Participants were 571 patients seen as part of a hospital trauma service who had acute traumatic brain injuries, and 228 patients involved in head injury litigation. As expected, the hospital patients with more severe traumatic brain injuries performed more poorly than the patients with less severe brain injuries on Trails A and Trails B. Cutoff score tables were developed for the patients with acute traumatic brain injuries for the total sample and by injury severity groups. Scores falling at or below the 5th percentile were considered suspicious for possible exaggeration. The performances of the head injury litigants who exaggerated on at least one well-validated symptom validity test were compared to these cutoffs. Very high positive predictive values for individuals with very mild head injuries on Trails A and B were identified (i.e., both 100%); lower positive predictive values were obtained for individuals with more severe head injuries (55.6-60%). The negative predictive values were only moderate (range=66.4-78.2%), and the sensitivity was very low (range = 7.1-18.5%) for all groups. Scores that fall in the range of possible biased responding should be considered "red flags" for the clinician because they likely do not make biological or psychometric sense. However, the sensitivity of the test for deliberate exaggeration is very low, so clinicians who rely on this test in isolation to identify deliberately poor performance will fail to identify the vast majority of cases.     

Using the Wechsler Memory Scale-III to detect malingering in mild traumatic brain injury

This study examined the classification accuracy of the WMS-III primary indices in the detection of Malingered Neurocognitive Dysfunction (MND) in Traumatic Brain Injury (TBI) using a known-groups design. Sensitivity, specificity, and positive predictive power are presented for a range of index scores comparing mild TBI non-malingering (n = 34) and mild TBI malingering (n = 31) groups. A moderate/severe TBI non-malingering (n = 28) and general clinical group (n = 93) are presented to examine specificity in these samples. In mild TBI, sensitivities for the primary indices ranged from 26% to 68% at 97% specificity. Three systems used to combine all eight index scores were also examined and all achieved at least 58% sensitivity at 97% specificity in mild TBI. Specificity was generally lower in the moderate/severe TBI and clinical comparison groups. This study indicates that the WMS-III primary indices can accurately identify malingered neurocognitive dysfunction in mild TBI when used as part of a comprehensive classification system.     

Derived trail making test cutoffs and malingering among substance abusers

The Trail Making test (TMT) is often used to screen for cognitive impairment in substance abusers. A possible limitation of the TMT in clinical settings is that substance abusers may malinger and give poor effort. Data from the Drug Abuse Treatment Outcome Study (DATOS) were analyzed to develop derived TMT cutoffs. Data were analyzed to determine number of substance abusers that fell beyond the upper end of the distribution of selected derived TMT scores at the 10, 5, and 1 percentiles. These percentiles were set for alcoholics (n = 1000), cocaine abusers (n = 4306), and heroin abusers (n = 1548) for TMT selected derived scores. Inspection of the selected TMT derived scores yielded an impression that the percentile values for the 3 sub-samples of primary drugs of abuse, alcohol, cocaine, and heroin, are actually very similar at each of the 3 percentile levels. This would suggest that these estimates are actually quite stable and reinforces the notion that they may be creditable estimates. The proper use of the derived TMT cutoff scores is to alert clinicians to the increasingly higher probability of poor effort when a substance abuser in one of the three groups scores beyond the one percent cutoff for the primary drug of abuse sample. Clearly, the use of these cutoffs needs further empirical validation before they would be considered as a single source to suggest malingering. Great caution is suggested in using these cutoff scores for clinical purposes with substance abusing patients in their current state of validation. In short, further research is warranted.     

Prospective memory assessment in acute mild traumatic brain injury

Abstract

Objective: Prospective memory (PM) is the ability to remember to perform an intention at the appropriate time in the future. It is of primary importance for daily living, and its disruption may impact functional autonomy. To date, few studies have examined PM during the acute phase of mild traumatic brain injury (mTBI), despite the high prevalence of this neurological condition and its potential impact on cognition.

Method: Twenty mTBI patients (time since injury ranged from 45 to 73?days) and 15 healthy control participants performed the Ecological Test of Prospective Memory (TEMP), a simulated errand task in which participants were required to execute 10 event-based (EB) and five time-based (TB) tasks. The TEMP separately evaluates PM phases as well as prospective and retrospective components in event- and time-based conditions. Participants also completed a neuropsychological test battery. Correlations were performed between cognitive composite scores and the TEMP.

Results: mTBI patients experienced difficulty in learning the content of intentions, retrieving these intentions in the time-based condition (prospective component) and recalling the associated actions in the event- and time-based conditions (retrospective component). Retrospective memory composite score was correlated with the learning and retention phases of the TEMP, whereas attention/working memory and executive composite scores were correlated with the time-based condition and performance on the ongoing task.

Conclusion: These results suggest the presence of global PM impairment during the acute phase of mTBI, as well as impairment of retrospective memory, attention/working memory, and executive functions, which are key components for PM performance.     

Interpreting the trail making test following traumatic brain injury: comparison of traditional time scores and derived indices

The purpose of this study was to examine the clinical application of traditional time scores and various derived indices from the Trail Making Test (TMT) in a sample of 571 patients with acute traumatic brain injury (TBI). Participants were classified into four injury severity groups. A clear linear relation between injury severity and TMT performance was demonstrated, with the more severely brain injured patients performing more poorly on most measures. Hierarchical logistic regression analysis of TMT time scores across binary extreme groups based on injury severity resulted in high classification rates for patients with very mild TBI (93.0% correctly classified) and low classification rates for patients with moderate to severe TBI (50.0% correctly classified). However, TMT derived indices did not provide a unique contribution to test interpretation beyond what is already available from Part A and B separately.     

Anxiety and trail making test scores in a sample of cocaine abusers

Anxiety effects on the Trail Making test (TMT), a test often used for screening for cognitive impairments, were examined in a sample of cocaine abusers in drug abuse treatment programs. A mixed race sample of 4306 subjects was drawn from electronic files of data from the Drug Abuse Treatment Outcome Study (DATOS). The DATOS was a naturalistic, prospective cohort study that collected data from 1991-1993 in 96 programs in 11 cities in the United States. Data were analyzed to determine the effects of anxiety on the TMT scores A and B, and also derived indices created by adding, subtracting, multiplying, and dividing parts A and B of the TMT in this large treatment sample of cocaine abusers. The variables of sex, age, ethnicity, and education were included in analyses to control for demographic effects. The ratio derived score was the least sensitive TMT score to the effects of anxiety, but all TMT R-squares were quite small.     

Depression and trail making test scores in a sample of cocaine abusers

Depression effects on the Trail Making test (TMT), a test often used for screening cognitive impairments, were examined in a sample of cocaine abusers in drug abuse treatment programs. A mixed race sample of 4299 subjects was drawn from electronic files of data from the Drug Abuse Treatment Outcome Study (DATOS). DATOS was a naturalistic, prospective cohort study that collected data from 1991-1993 in 96 programs in 11 cities in the United States. Data were analyzed to determine the effects of depression on the TMT scores A and B, and also derived indices created by adding, subtracting, multiplying, and dividing parts A and B of the TMT in this large treatment sample of cocaine abusers. The variables of sex, age, ethnicity, and education were included in analyses to control for demographic effects. The TMT part A and the difference score were the least sensitive TMT scores to the effects of depression but all TMT R-squares were quite small.     

Neuropsychological assessment of distractibility in mild traumatic brain injury and depression

Traditional neuropsychological assessments are conducted exclusively in a quiet, distraction-free environment; clients' abilities to operate under busy and distracting conditions remain untested. Environmental distractions, however, are typical for a multitude of real-life situations and present a challenge to clients with frontal-temporal brain injury. In an effort to improve ecological validity, an extension of the traditional neuropsychological assessment was developed, comprising a standardized distraction condition. This allowed cognitive functions to be tested both in the traditional setting and with exposure to a specified audio-visual distraction. The present study (n = 240) investigated how clients with mild Traumatic Brain Injury (mTBI) (n = 80), Major Depression (MDE) (n = 80), and a healthy control sample (n = 80) performed on sub-tests of the Wechsler Adult Intelligence Scale-IV and the Wechsler Memory Scale-IV both in the standard and the distraction conditions. Test effort was controlled. Significant deterioration of performance in the distraction setting was observed among clients with mTBI. In contrast the performance of a healthy control sample remained unchanged. Significant improvement of performance in the distraction setting was documented for clients with MDE. Contrary to their improved performance, depressed clients experienced the distraction setting as more distressing than the control and mTBI group.     

Classification accuracy of the test of memory malingering in traumatic brain injury: results of a known-groups analysis

This study used a known-groups design to determine the classification accuracy of the Test of Memory Malingering (Tombaugh, 1996, 1997) in detecting cognitive malingering in traumatic brain injury (TBI). Forty-one of 161 TBI patients met Slick, Sherman, and Iverson (1999) criteria for Malingered Neurocognitive Dysfunction. Twenty-two no-incentive memory disorder patients were also included. The original cutoffs (<45) for Trial 2 and Retention demonstrated excellent specificity (less than a 5% false positive error rate) and impressive sensitivity (greater than 45%). However, these cutoffs are actually conservative in the context of mild TBI. Over 90% of the non-MND mild TBI sample scored 48 or higher on the Retention Trial and none scored less than 46 while 60% of the MND patients claiming mild TBI were detected at those levels. Trial 1 also demonstrated excellent classification accuracy. Application of these data to clinical practice is discussed.     

Derived trail making test indices in a sample of sedative abusers: demographic effects

Derived indices on the Trail Making test (TMT), a test often used to screen for cognitive impairment, were examined in a sample of 72 sedative abusers in drug abuse treatment programs. A mixed race sample was drawn from electronic files of data from the Drug Abuse Treatment Outcome Study (DATOS). The DATOS was a naturalistic, prospective cohort study that collected data from 1991-1993 in 96 programs in 11 cities in the United States. Data were analyzed to determine the effects of demographic variables on derived indices created by adding, subtracting, multiplying, and dividing parts A and B of the TMT in this large treatment sample of substance abusers. The variables of sex, age, ethnicity, and education were not statistically significant for selected derived indices of the TMT.     

Derived trail making test indices in a sample of hallucinogen abusers: demographic effects

Derived indices on the Trail Making test (TMT), a test often used for screening for cognitive impairment, were examined in a sample of hallucinogen abusers in drug abuse treatment programs. A mixed race sample (N = 128) was drawn from electronic files of data from the Drug Abuse Treatment Outcome Study (DATOS). The DATOS was a naturalistic, prospective cohort study that collected data from 1991 to 1993 in 96 programs in 11 cities in the United States. Data were analyzed to determine the effects of demographic variables on derived indices created by adding, subtracting, multiplying, and dividing Parts A and B of the TMT in this large treatment sample of hallucinogen abusers. The variables of sex and age were not statistically significant for derived indices of the TMT. The variable of ethnicity was significant for the all derived indices except the ratio score (divide Part B by Part A) and the variable of education was significant for the interaction score (multiply Part A by Part B and divide by 100).     

Derived trail making test indices in a sample of alcohol abusers: demographic effects

Derived indices on the Trail Making test (TMT), a test often used for screening cognitive impairments, were examined in a sample of alcohol abusers in drug abuse treatment programs. A mixed race sample of 1000 subjects was drawn from electronic files of data from the Drug Abuse Treatment Outcome Study (DATOS). The DATOS was a naturalistic, prospective cohort study that collected data from 1991-1993 in 96 programs in 11 cities in the United States. Data were analyzed to determine the effects of demographic variables on derived indices created by adding, subtracting, multiplying, and dividing parts A and B of the TMT in this large treatment sample of alcohol abusers. The variables of age, ethnicity, and education were statistically significant for the total (A + B), interaction (A x B/100), and difference score (B-A) derived indices of the TMT. The ratio score (B/A) was only significant for education.     

Derived trail making test indices in a sample of marijuana abusers: demographic effects

Derived indices on the Trail Making Test (TMT), a test often used for screening for cognitive impairment, were examined in a sample of marijuana abusers in drug abuse treatment programs. A mixed-race sample of 259 subjects was drawn from electronic files of data from the Drug Abuse Treatment Outcome Study (DATOS). The DATOS was a naturalistic, prospective cohort study that collected data from 1991 to 1993 in 96 programs in 11 cities in the United States. Data were analyzed to determine the effects of demographic variables on derived indices created by adding, subtracting, multiplying, and dividing Parts A and B of the TMT in this large treatment sample of marijuana abusers. The variables of age, ethnicity, and education were statistically significant for the total (A + B), and interaction (A x B/100) derived indices of the TMT. The difference score (B - A) was significant only for ethnicity and the ratio score (B/A) was not significant for any demographic variable.     

Derived trail making test indices in a sample of substance abusers: demographic effects

Derived indices on the Trail Making Test (TMT), a test often used to screen for cognitive impairments, were examined in a sample of substance abusers in drug abuse treatment programs. A mixed race sample was drawn from electronic files of data from the Drug Abuse Treatment Outcome Study (DATOS). The DATOS was a naturalistic, prospective cohort study that collected data from 1991 through 1993 within 96 programs in 11 cities in the United States. Data were analyzed to determine the effects of demographic variables on derived indices created by adding, subtracting, multiplying, and dividing parts A and B of the TMT in this large treatment sample of substance abusers. The variables of sex, age, ethnicity, and education were statistically significant for selected derived indices of the TMT.     

Derived trail making test indices in a sample of heroin abusers: demographic effects

Derived indices on the Trail Making test (TMT), a test often used for screening cognitive impairment, are examined in a sample of heroin abusers in drug abuse treatment programs. A mixed race sample of 1548 subjects was drawn from electronic files of data from the Drug Abuse Treatment Outcome Study (DATOS). The DATOS was a naturalistic, prospective cohort study that collected data from 1991-1993 in 96 programs in 11 cities in the United States. Data were analyzed to determine the effects of demographic variables on derived indices created by adding, subtracting, multiplying, and dividing parts A and B of the TMT in this large treatment sample of heroin abusers. The variables of sex, age, ethnicity, and education were strongly statistically significant for the total (A + B) and interaction (A x B/100) derived indices of the TMT. Similarly, the difference score (B - A) was significant for race/ethnicity and education, but the ratio score (B/A) was not significant for any demographic variable.     

Recovery from mild traumatic brain injury

BACKGROUND: Fatigue is one of the most frequently reported symptoms after Mild Traumatic Brain Injury (MTBI). To date, systematic and comparative studies on fatigue after MTBI are scarce, and knowledge on causal mechanisms is lacking. OBJECTIVES: To determine the severity of fatigue six months after MTBI and its relation to outcome. Furthermore, to test whether injury indices, such as Glasgow Coma Scale scores, are related to higher levels of fatigue. METHODS: Postal questionnaires were sent to a consecutive group of patients with an MTBI and a minor-injury control group, aged 18-60, six months after injury. Fatigue severity was measured with the Checklist Individual Strength. Postconcussional symptoms and limitations in daily functioning were assessed using the Rivermead Post Concussion Questionnaire and the SF-36. RESULTS: A total of 299 out of 618 eligible (response rate 52%) MTBI patients and 287 out of 482 eligible (response rate 60%) minor-injury patients returned the questionnaire. Ninety-five MTBI patients (32%) and 35 control patients (12%) were severely fatigued. Severe fatigue was highly associated with the experience of other symptoms, limitations in physical and social functioning, and fatigue related problems like reduced activity. Of various trauma severity indices, nausea and headache experienced on the ED were significantly related to higher levels of fatigue at six months. CONCLUSIONS: In conclusion, one third of a large sample of MTBI patients experiences severe fatigue six months after injury, and this experience is associated with limitations in daily functioning. Our finding that acute symptoms and mechanism of injury rather than injury severity indices appear to be related to higher levels of fatigue warrants further investigation.     

Outcome from mild traumatic brain injury

PURPOSE OF REVIEW: The focus of this review is outcome from mild traumatic brain injury. Recent literature relating to pathophysiology, neuropsychological outcome, and the persistent postconcussion syndrome will be integrated into the existing literature. RECENT FINDINGS: The MTBI literature is enormous, complex, methodologically flawed, and controversial. There have been dozens of studies relating to pathophysiology, neuropsychological outcome, and the postconcussion syndrome during the past year. Two major reviews have been published. Some of the most interesting prospective research has been done with athletes. SUMMARY: The cognitive and neurobehavioral sequelae are self-limiting and reasonably predictable. Mild traumatic brain injuries are characterized by immediate physiological changes conceptualized as a multilayered neurometabolic cascade in which affected cells typically recover, although under certain circumstances a small number might degenerate and die. The primary pathophysiologies include ionic shifts, abnormal energy metabolism, diminished cerebral blood flow, and impaired neurotransmission. During the first week after injury the brain undergoes a dynamic restorative process. Athletes typically return to pre-injury functioning (assessed using symptom ratings or brief neuropsychological measures) within 2-14 days. Trauma patients usually take longer to return to their pre-injury functioning. In these patients recovery can be incomplete and can be complicated by preexisting psychiatric or substance abuse problems, poor general health, concurrent orthopedic injuries, or comorbid problems (e.g. chronic pain, depression, substance abuse, life stress, unemployment, and protracted litigation).     

Functional connectivity in mild traumatic brain injury

Objectives: Research suggests that the majority of mild traumatic brain injury (mTBI) patients exhibit both cognitive and emotional dysfunction within the first weeks of injury, followed by symptom resolution 3–6 months postinjury. The neuronal correlates of said dysfunction are difficult to detect with standard clinical neuroimaging, complicating differential diagnosis and early identification of patients who may not recover. This study examined whether resting state functional magnetic resonance imaging (fMRI) provides objective markers of injury and predicts cognitive, emotional, and somatic complaints in mTBI patients semiacutely (<3 weeks postinjury) and in late recovery (3–5 month) phases. Methods: Twenty‐seven semiacute mTBI patients and 26 gender, age, and education‐matched controls were studied. Fifteen of 27 patients returned for a follow‐up visit 3–5 months postinjury. The main dependent variables were spontaneous fluctuations (temporal correlation) in the default‐mode (DMN) and fronto‐parietal task‐related networks as measured by fMRI. Results: Significant differences in self‐reported cognitive, emotional, and somatic complaints were observed (all P < 0.05), despite normal clinical (T1 and T2) imaging and neuropsychological testing results. Mild TBI patients demonstrated decreased functional connectivity within the DMN and hyper‐connectivity between the DMN and lateral prefrontal cortex. Measures of functional connectivity exhibited high levels of sensitivity and specificity for patient classification and predicted cognitive complaints in the semi‐acute injury stage. However, no changes in functional connectivity were observed across a 4‐month recovery period. Conclusions: Abnormal connectivity between the DMN and frontal cortex may provide objective biomarkers of mTBI and underlie cognitive impairment. Hum Brain Mapp, 2011. © 2011 Wiley‐Liss, Inc.     

Neuroimaging findings in mild traumatic brain injury

The role of neuroimaging in the diagnosis and management of mild traumatic brain injury (TBI) is evolving. In general, the structural imaging techniques play a role in acute diagnosis and management, while the functional imaging techniques show promise for clarification of pathophysiology, symptom genesis, and mechanisms of recovery. A wide array of neuropathological processes are involved in mild TBI including changes in bone (e.g., a skull fracture), tissue density and water content (edema), blood flow, white matter integrity and pathway connectivity (diffuse axonal injury), and subtle changes in the neuronal and extracellular biochemical milieu. No single imaging technique is capable of addressing all these processes. It is, therefore, important to be aware of the advantages and limitations of the various available imaging modalities. This paper selectively reviews the pertinent literature on the structural and functional imaging in mild TBI.     

Microenvironment changes in mild traumatic brain injury

Traumatic brain injury (TBI) is a major public-health problem for which mild TBI (MTBI) makes up majority of the cases. MTBI is a poorly-understood health problem and can persist for years manifesting into neurological and non-neurological problems that can affect functional outcome. Presently, diagnosis of MTBI is based on symptoms reporting with poor understanding of ongoing pathophysiology, hence precluding prognosis and intervention. Other than rehabilitation, there is still no pharmacological treatment for the treatment of secondary injury and prevention of the development of cognitive and behavioural problems. The lack of external injuries and absence of detectable brain abnormalities lend support to MTBI developing at the cellular and biochemical level. However, the paucity of suitable and validated non-invasive methods for accurate diagnosis of MTBI poses as a substantial challenge. Hence, it is crucial that a clinically useful evaluation and management procedure be instituted for MTBI that encompasses both molecular pathophysiology and functional outcome. The acute microenvironment changes post-MTBI presents an attractive target for modulation of MTBI symptoms and the development of cognitive changes later in life.